1) Field of the Invention
The field of the present invention generally relates to lighting systems and, more particularly, to control networks for lighting systems used in transit vehicles or conveyances such as buses, lightrail cars, and the like.
2) Background
Transit vehicles and similar conveyances typically rely on fluorescent lighting to provide illumination, in part because of the historical efficiency of such lighting as compared to, e.g., incandescent lighting. However, fluorescent lighting has drawbacks and limitations.
For example, fluorescent lighting has a relatively short lifetime and a high current draw as compared to some other types of lighting, in particular low power light-emitting diodes (LEDs). In a typical setting, the fluorescent lights receive power from the transit vehicle's battery, which is usually 24 volts, the output of which is “chopped” to provide an alternating current source. The nature of fluorescent lights leads to high electro-magnetic fields, making compatibility with other electrical equipment challenging. Fluorescent lights also often have problems with arcing, which in turn can pose fire dangers or else blow out electrical components and/or cause power ripples. Fluorescent lights are also traditionally wired in a point-to-point fashion, requiring a substantial amount of wiring.
In addition, fluorescent lighting is not very amenable to flexible control, and can be difficult to dim. For example, if the fluorescent lamp filaments get too cool when attempting to dim the lamp, then the lamp may simply go out. If current continues to flow while the electrodes are at an improper temperature, then severe rapid degradation of the filaments is possible.
Some efforts have been made to try to incorporate LED lights in transit vehicles, but it is not clear that such efforts have been able to overcome the many disadvantages and limitations of fluorescent lighting.
It would therefore be advantageous to provide a lighting system for a transit vehicle or conveyance, which overcomes one or more of the disadvantages or limitations of conventional lighting systems. It would further be advantageous to provide such a lighting system which has improved lifetime and power/current consumption, requires less wiring, and/or is more easily controlled. It would also be advantageous to provide such a lighting system which is inexpensive and not overly complex to implement or deploy, and/or has other benefits and advantages not found in conventional transit vehicle lighting systems.